Basic Matrix Operations

Julia provides common linear algebra operations in the LinearAlgebra package, and one convenient use of Julia is to create data for tests written in other programming languages.

julia> using LinearAlgebra

In Julia the rows of the matrices are separated by a semi-colon ;:

julia> M1 = [0.285714  0.857143 -0.428571 0.0;
               -0.857143 0.428571 0.285714 0.0;
               0.428571 0.285714 0.857143 0.0;
               1.0 2.0 3.0 1.0]
4×4 Matrix{Float64}:
  0.285714  0.857143  -0.428571  0.0
 -0.857143  0.428571   0.285714  0.0
  0.428571  0.285714   0.857143  0.0
  1.0       2.0        3.0       1.0

To get accurate data for the test of the Math::Inverse function in HCCVectorMath.h using Julia:

julia> inv(M1)
4×4 Matrix{Float64}:
  0.285714  -0.857143   0.428571  -2.77556e-17
  0.857143   0.428571   0.285714   2.77556e-17
 -0.428571   0.285714   0.857143   0.0
 -0.714288  -0.857142  -3.57143    1.0

Now, the data can be copied from the Julia console and pasted into a unit test for the Math::Inverse function.

BOOST_AUTO_TEST_CASE( InverseTest1 )
{
    using namespace Harlinn::Common::Core::Math;
    SquareMatrix<float, 4> matrix( 0.285714f,  0.857143f, -0.428571f, 0.0f,
                                        -0.857143f, 0.428571f, 0.285714f, 0.0f,
                                        0.428571f, 0.285714f, 0.857143f, 0.0f,
                                        1.0f, 2.0f, 3.0f, 1.0f );

    SquareMatrix<float, 4> expected( 0.285714f, -0.857143f, 0.428571f, 0.0f,
                                        0.857143f, 0.428571f, 0.285714f, 0.0f,
                                        -0.428571f, 0.285714f, 0.857143f, 0.0f,
                                        -0.714286f, -0.857143f, -3.57143f, 1.0f );

    auto inverse = Inverse( matrix );

    auto equal = Equal( inverse.value(), expected );

    BOOST_CHECK( equal );
}